Hypoglycemia Linked With Mortality in Hospitalized Diabetic Patients

Laurie Barclay, MD

July 13, 2009

July 13, 2009 — In diabetic patients hospitalized in the general ward, hypoglycemia is common and is associated with an increased length of stay (LOS) and higher mortality rate, according to the results of a retrospective cohort study reported in the July issue of Diabetes Care.

"Hypoglycemia is associated with adverse outcomes in mixed populations of patients in intensive care units," write Michael E. Matheny, MD, MS, MPH, from the Brigham and Women's Hospital in Boston, Massachusetts, and colleagues. "It is not known whether the same risks exist for diabetic patients who are less severely ill. In this study, we aimed to determine whether hypoglycemic episodes are associated with higher mortality in diabetic patients hospitalized in the general ward."

Between January 2003 and August 2004, a total of 2582 patients with diabetes had a total of 4368 admissions to the general ward of a teaching hospital. Using multivariable analysis, the investigators examined associations between the number and severity of hypoglycemic episodes and inpatient mortality, LOS, and mortality within 1 year after hospital discharge.

Hypoglycemia, defined as a blood glucose level of 50 mg/dL or less, occurred in 7.7% of admissions. For every additional day with hypoglycemia, there was an increase in LOS by 2.5 days (P < .0001), in the odds of inpatient death by 85.3% (P = .009), and in the odds of death within 1 year from discharge by 65.8% (P = .0003). For every 10-mg/dL decrease in the lowest blood glucose level recorded during hospitalization, the odds of death during hospitalization were increased 3-fold (P = .0058).

"Hypoglycemia is common in diabetic patients hospitalized in the general ward," the study authors write. "Patients with hypoglycemia have increased LOS and higher mortality both during and after admission. Measures should be undertaken to decrease the frequency of hypoglycemia in this high-risk patient population."

Limitations of this study include retrospective analysis, precluding determination of causality; inclusion only of patients admitted to a single academic hospital in Boston; and inability to distinguish type 1 from type 2 diabetes. Other limitations include lack of nutrition information for individual patients, lack of data regarding immediate clinical sequelae, and use of point-of-care blood glucose levels.

"Extra care should be taken to prevent hypoglycemic events in this population already at high risk for adverse events, with particular attention being paid to matching the antihyperglycemic regimen to the nutritional intake," the study authors conclude. "At the same time, hypoglycemia among diabetic patients in the general ward could be interpreted as a warning sign of an impending clinical deterioration. It could therefore serve as a useful indicator for the necessity of increased monitoring, more aggressive treatment of infections, transitioning to a more intensive care setting, and case management."

This study was supported in part by grants from the Diabetes Action Research and Education Foundation and the National Library of Medicine. The study authors have disclosed no relevant financial relationships.

Diabetes Care. 2009;32:1153-1157.